5. Innovative VFD Transformations
With its unique operating characteristics, vortex fluidic technology
warrants consideration for preparing/transforming nanomaterial, as a
paradigm shift for preparing material with unique properties, for niche
innovative research and industrial applications. For instance, it has
been shown that enzymatic reactions could be accelerated using a VFD,
with pressure waves effective in accelerating enzymatic
reactions24. Despite chemical transformations being
catalyzed with outstanding regio- and stereo-specificities, extended
reaction times limit numerous enzymes. However, Britton et al.found that the above pressure waves generated at specific rotational
speeds allow an enzyme to respond, providing an acceleration landscape,
Figure 8. Enzymatic efficiency (kcat/Km)
and rate constants (kcat) have been increased, with an
average 15-fold enhancement for deoxyribose-5-phosphate aldolase, an a
seven-fold average acceleration displayed by four other enzymes. The VFD
increase the mass transfer such that the chattering events for the
enzyme are more likely to be successful, with negative pressure
collapsing the transition, ie. mechanically changing the secondary
structure of the enzyme. More recently, the fabrication of hybrid
laccase-Cu3(PO4)2nanoflowers via an intermediate toroidal structure is dramatically
accelerated in the VFD. This innovative approach leads to the formation
of the composite material with enhanced catalytic activity (1.8 fold)
compared to free laccase under diffusion control.25Following the fabrication process, the hybrid nanoflowers are
subsequently integrated as a coating on the side wall of the reactor
surface. The resulting coating exhibits exceptional stability and
reusability. This remarkable durability enables a significant 16-fold
enhancement in catalytic rates compared to the control conditions.
The VFD has also been utilized to procure a rapid protein refolding
technique, with yields for proteins being increased for simple cell
lines, not to mention lowering costs, reducing streams of waste, and
significantly reducing the time associated with protein expression for
an extensive range of research and industrial applications, as reported
by Yuan et al. 27 The shear stresses from fluid
films micrometer wide have been observed in refolding lysozyme in hen
egg-whites, Figure 8. Recombinant lysozyme in hen egg-whites and
caveolin-1, and a protein much larger in size, cAMP-dependent protein
kinase A, all of which require only minutes for processing, thereby
being much faster than overnight dialysis by conventional means. In
recent advancements, the ability to manipulate the unfolding and
refolding of β-lactoglobulin has been established using the technology,
aided by the monitoring of aggregation-induced emission luminogen
(AIEgen).50 The AIEgen have been intensively explored
in the biomedical field51 and in this case they serve
as a monitoring tool, enabling real-time observation of the folding
behavior of the protein during the processes. Furthermore, solutions
with larger volumes can be accommodated, with the VFD scaling up through
multiple units for parallel processing or the continuous mode,
consequently dramatically lowering financial costs and time for
refolding inactive proteins on an industrial scale.